Wisconsin's annual temperature has warmed an average of 1.3 degrees between 1950 and 2006.

Winter temperatures have risen 2.5 degrees during the same period.

Summer temperatures have increased 0.5 degrees from 1950 to 2006.

The first detailed research on Wisconsin's climate is forecasting a jump in average annual temperatures of 4 to 9 degrees Fahrenheit by midcentury, which could push humans and nature to adapt to weather conditions that at times resemble Missouri today.

The findings are unique for climate research in Wisconsin because researchers are making predictions about the future on a local scale.

Climate scientists at the University of Wisconsin-Madison said Monday that warming will be greatest in northern Wisconsin, with the smallest changes taking place in the south along Lake Michigan.

Winters are expected to be warmer and summers are forecast to change the least.

Still, the researchers found that the number of days where high temperatures exceed 90 degrees could double to 25 each year in southern Wisconsin between 1980 and 2055; it could triple for the same period to 12 times a year in northern Wisconsin.

The UW study was led by Dan Vimont, an assistant professor of atmospheric and oceanic sciences, and Chris Kucharik, an assistant professor of agronomy and environmental sciences.

The research suggests profound changes in the decades to come. But rather than targeting policy-makers, the findings will go to an organization that was formed in 2007 whose members include UW, the Department of Natural Resources and other agencies, and business groups.

The Wisconsin Initiative on Climate Change Impacts is trying to identify and measure the implications of global warming in the state. The study mirrors the conclusions of other climate research - notably, the 2007 Intergovernmental Panel on Climate Change. The panel concluded that burning of fossil fuels, such as coal, gasoline and oil, has contributed to a warming of the Earth's atmosphere.

Another group, the Union of Concerned Scientists, has concluded that Wisconsin winters could be more like Missouri's today.

"This study highlights the very local effects of global warming that towns, counties and states will have to address to effectively adapt to climate change," said Peter Frumhoff, director of science and policy at Union of Concerned Scientists in a statement. Frumhoff was an author on land-use issues for the Intergovernmental Panel on Climate Change report.

"We need more studies like this one because much of the responsibility for adaptation ultimately will rest with individual localities," he said.

'Clearer picture'

State climatologist John Young said the significance of the UW report is that most climate forecasts "are a bit too coarse to distinguish between Wisconsin and Illinois."

The work "gives us a clearer picture of the possibilities of climate change on a smaller scale," he added.

Kucharik and a graduate student gathered weather data from 170 observers across the state and constructed the observers' reports into a grid of 25 square miles that includes local land forms and bodies of water.

Their findings:

• Wisconsin's annual temperature has warmed an average of 1.3 degrees between 1950 and 2006.

• In the winter, temperatures have risen 2.5 degrees during the same period. Winter temperatures in northwestern Wisconsin have increased the most - an average of more than 4 degrees.

• In the summer, temperatures have increased modestly - 0.5 degrees from 1950 to 2006.

As for future temperatures, Vimont and his collaborators modeled the period from 1980 to 2055.

They found:

• Warming is forecast to be the greatest in the winter, with annual increases that range from 5 degrees to 11 degrees by 2055, with the biggest increases projected for the northwest.

• Warming is expected to be less in the summer, with annual increases of 3 to 8 degrees by 2055. The north is again expected to feel the brunt of the increase.

• Winter precipitation is expected to increase by an average of 0.1 inches to 1.3 inches a year, with northern Wisconsin experiencing a 20% increase in winter precipitation.

Vimont said it's unclear why northern Wisconsin would exhibit greater changes. But Young said it could be the heat-trapping effects of greenhouse gases. Also, higher temperatures increase moisture and could increase cloud cover. Clouds could keep night temperatures from falling as much.

But climate forecasting is measured over decades, not individual years, he said.

Planning for change

"I think you get worried when you don't know how much change will occur, and you don't have a plan for what you are going to do when it does occur," Vimont said.

"This data tell us how much change to expect, so I think that it addresses this sense of alarm."

In Wisconsin, the Doyle administration launched the Governor's Task Force on Global Warming in 2007 and recommended goals to cut greenhouse gas emissions by 22% in 2022 and by 75% in 2050.

Vimont and Kucharik steered clear of policy. They discussed their findings Monday with members of the Wisconsin Initiative on Climate Change Impacts.

"This is our first cut," said Jack Sullivan, director of the DNR's Bureau of Integrated Science Services and a member of the group's science council. "We're really in our infancy in this, and we anticipate that we will have better answers as time goes on."

For now, Sullivan said natural resources managers are trying to plan how they can adapt to a changing climate.

Brook trout, for example, need cold water, so Sullivan said the DNR might need to re-orient stocking and habitat work farther north.

Trees are another consideration. The DNR runs nurseries to replant public forests and provide nursery stock for private property owners. It might need to change the mix of tree species that favor a warmer climate.